Antimatter containment

Antimatter containment was the process whereby antimatter and matter were kept separated by the use of magnetic fields to prevent the oppositely charged particles from colliding, which would result in the mutual destruction of the matter and antimatter, along with a violent and explosive release of pure energy according to Einstein's formula E=mc2.

Antimatter containment was a key function of a starshipwarp core which used both antimatter and matter, released in controlled and balanced amounts, to provide energy which powers the ship's warp drive.

Galaxy-class starships in the 24th century had a system of seven independent computer safety locks to prevent antimatter containment from being breached, assuming that there was no damage to the warp core components. (TNG: "Contagion")

If the antimatter containment field strength dropped below 15% on a Galaxy-class starship, the field would collapse, destroying the ship. (TNG: "Disaster")